The present invention relates to a catalytic burning apparatus for effecting oxidizing reactions of liquid or gaseous fuel on a solid oxidizing catalyst, and also to a method of catalytic burning.
In a catalytic burning apparatus and a catalytic burning method, after mixing the air with liquid or gaseous fuel, this mixed gas is catalytically oxidized by a catalyst. Flameless catalytic burning then occurs. Heretofore, a catalytic burning apparatus using gas which is produced by mixing air with gaseous fuel have been proposed. The above described conventional catalytic burning apparatus is described in U.S. Pat. No. 5,158,448 which is incorporated herein by reference and explained with reference to FIG. 3.
FIG. 3 shows a conventional catalytic burning apparatus. In FIG. 3 a mixing room 12 is used for mixing fuel with air. Flame ports 13 are disposed downstream along with the flow of premixed gas of the mixing room 12. An ignition plug 15 and a flame rod 16 are disposed near the flame ports 13, and a catalyst layer 14 is disposed downstream along the flow of premixed gas of the flame ports 13. The catalyst layer 14 has a plurality of communicating holes 14a. The operation of the apparatus is carried out by the following steps.
(1) A step of activating the ignition plug 15 for forming a flame at the flame ports 13. PA1 (2) A step of extinguishing the flame after a lapse of a predetermined time length by stopping the fuel supply, and PA1 (3) A step of starting a catalytic burning reaction on the surface of the catalyst layer 14 by supplying fuel again without activating the ignition plug 15. PA1 (1) A catalytic burning apparatus and a catalytic burning method are disclosed by which room temperature can be adjusted according to its capacity in wide range. PA1 (2) A catalytic burning apparatus and a catalytic burning method are disclosed by which a room can be heated with little offensive smell. PA1 (3) A catalytic burning apparatus and a catalytic burning method are disclosed by which room temperature can be maintained at a pre-determined level with small fluctuation.
The operation is controlled in such manner that, in the flame forming step at the flame ports 13, the burning is stopped when the flame rod 16 as an ion current detecting means does not detect a predetermined electric current. In the catalytic burning step at the catalyst layer 14, the burning is stopped, in contrast with the above, when the flame rod 16 detects the predetermined electric current.
However, the above described catalytic burning apparatus has the following disadvantages. First, to adjust the temperature of the room, the catalytic burning must be turned on and off which creates an offensive smell. Second, when using the above described apparatus for heating, there is little allowance for the room capacity, since heating power is determined by the size of the catalytic layer.